模拟酸雨对白筋叶片抗氧化酶活性及叶绿素荧光参数的影响

采用棚内盆栽方法, 设置pH值5.6 （对照）、4.0、3.0和2.0的模拟酸雨胁迫试验, 探讨其对白簕幼苗叶片MDA含量、保护酶活性、叶绿素含量、气体交换参数和叶绿素荧光参数的影响。结果表明, 随着模拟酸雨pH值的降低, MDA含量呈先降低后升高的趋势; SOD活性逐渐降低, POD活性逐渐升高, APX活性呈先升高后降低的变化。叶绿素a、叶绿素b、总叶绿素含量均比对照高, 在pH 4.0时达最大值。气孔限制值（Ls）、PSII实际光化学量子产量（ΦPSII）、光化学淬灭系数（qP）均随pH值的降低而下降, 净光速率（Pn）、气孔导度（Gs）、蒸腾速率（Tr）、水分利用效率（WUE）、PSII最大光化学效率（Fv/Fm）、PSII的潜在活性（Fv/Fo）、非光化学淬灭系数（qN）呈先升高后降低趋势, 且也都在pH 4.0时达最大值。由此推测, pH 4.0的酸雨处理有利于白簕幼苗的生长, 表明白簕幼苗可能喜欢生活在微酸环境中, 但是随着酸度加强, 反而起到抑制作用。

Effects of Simulated Acid Rain on Antioxidant Enzyme Activities and Chlorophyll Fluorescence Paramenters in Leaves ofAcanthopanax trifoliatus

In this study, the MDA content, antioxidant enzyme activities, chlorophyll content, gas exchange and chlorophyll fluorescence parameters of Acanthopanax trifoliatus were investigated under simulated acid rains of pH 5.6 （as the control）, pH 4.0, pH 3.0 and pH 2.0. The results showed that with the decline of pH of the simulated acid rain, the MDA content decreased at pH 4.0, and then increased gradually. The SOD, POD and APX activities showed different trends. The contents of Chl a, Chl b, and total Chl were higher than those in control, and reached the peak at pH 4.0. With the pH value decreased, stomatal·Limitation value （Ls）, PSII actual photochemical quantum yield （φpsn） and photochemical quenching coefficient （qP） decreased, while net photosynthetic rate （Pn）, stomatal conductance （Gs）, transpiration rate （Tr）, water use efficiency （WUE）, the efficiency of excitation capture by open PSII reaction centers （Fv/Fo）, the maximum quantum yield of PSII photochemistry （Fv/Fm） and the non-photochemical quenching （qN） increased firstly and then decreased, also reached the maximum at pH 4.0. Therefore, acid rain of pH 4.0 was conducive to the growth ofA. trifoliatus seedlings, which indicated that they liked living in light acidic environment, but with the acidity of strengthening, the growth would be inhibited.